A textBox doesnt allow a transfert coming from a form

Question

Hi!

 

I need to transfer the data I have inside of my txtName  to other textbox named txtBox1. Curiosly its doesnt allow textbox only label (as you can see). Why I need only textbox? Just because with the textbox where I need to put my data coming from txtName its in multiline mode. But not for a label. How can I resolv it please.

FormToPrint= new FormToPrint(); 

frmToPrint.label.Text = txtName .Text.ToString();

frmToPrint.Show();